Gas stream monitor

ABSTRACT

A gas stream monitor shall be provided that facilitates the adjustment of the reseat flow. 
     The gas stream monitor consists of a gas-tight casing whose interior is equipped with a seat for a reseat body that is movable inside the casing and is kept in open position against the flow direction by weight and/or spring force, in which the flow cross-section, surface area of the reseat body and the forces are determined in such a manner that gas stream monitor leaves its open position at a defined value of the reseat flow and is moved towards the seat of the casing, so that the gas conduit is closed in the shut position, and has outside the casing at least one manipulator to adjust the spring pre-tension and/or the stroke of the reseat body. 
     The gas stream monitor serves to automatically shut off gas conduits upon the occurrence of an inadmissible flow increase due to, e.g. a damaged gas conduit or a defective consumer.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a gas stream monitor that automatically shutsoff gas conduits in the event of an inadmissible flow increase asspecified in the introductory clause of the first patent claim.

Such gas stream monitors, employed in pipelines, e.g. upstream of gasvalves, gas appliances, etc., are available in a large variety ofdesigns. Their purpose is to discontinue gas supply if gas consumptionexceeds a predefined value.

WO 92/01184, for instance, describes a gas stream monitor of theabove-mentioned type which shuts a pipe system in case of damage butdoes not effect a premature shutting off of the supply line if aconsumer requires the gas volume corresponding to its rated output overa longer period. One valve in this so-called safety shut-off mechanismis designed as a disk valve.

The set-up of this valve is as follows: the valve body is fixed to avalve shaft that is movably arranged on either side in slide bearings inaxial valve direction and opposing the force of a spring. The valve diskis jointly acting with a valve seat supported by two flat rings whichsimultaneously serve as joints for the above-mentioned slide bearings.The flat rings are provided with cut-outs or breakthroughs.

The springiness of the spring and/or the reseating path of the valve areadjustable in order to exactly adapt the reseat flow to the type, natureand number of consumers. A nut is provided at the free end of the valveshaft for the adjustment of the reseating path of the valve, the nut isscrewed to a thread on the valve shaft An adjusting device, e.g. asecond nut between the two slide bearings, is provided to adjust thespringiness.

An automatic shut-off valve is also known from GB Patent 556,863. Thisshut-off valve consists of a tubelike casing with threaded connectionson either side. The casing is fitted with a flat ring withbreakthroughs, which ring has at its centre a slide bearing for alongitudinally moving valve shaft with a valve gate at its end whichacts together with a valve seat in the casing. A pressure spring, thatis supported on one side by the valve gate and at the other by the flatring, keeps the valve gate in the open position until the adjustedreseat flow is achieved. Also in this design the reseat flow is changedby a modification of the springiness adjustment by altering the tapdepth of the valve shaft into a hood, and thus the installation lengthof the spring.

A valve described in U.S. Pat. No. 3,794,077 has a similar set-up. Apressure spring, with breakthroughs, supported on one side by a slidebearing at the casing and on the other by a nut screwed to the valveshaft keeps the valve gate in the open position until the adjustedreseat flow is achieved. Also there, a changing of the nut position,which is secured against turning with a pin, on the valve shaft theinstallation length of the pressure spring is altered and thus thereseat flow altered by a change of the springiness.

The disadvantage of all those solutions is that the reseat flow can onlybe adjusted by interior manipulations of the gas stream monitor and,hence, respective provisions have to be made already duringmanufacturing. This means, however, that already then the specificapplication, i.e. the technical parameters of the consumers downstreamof the place of installation, have to be known. This is the reason whythere are specific gas stream monitors available for each application.

The following happens in the known gas stream monitors: after a shut-offdue to gas consumption in excess of the reseat flow, caused e.g. by adamaged gas conduit or a defective consumer, the gas stream monitor isre-opened after defect remediation by building up pressure on theconsumer side until the valve disk is lifting from the valve seat andthus the flow cross-section is released again. This procedure, however,is often very time-consuming.

An overflow aperture in the valve disk is another possibility where,following the remediation of the defect and shutting of all consumers,the overflow aperture facilitates a pressure build-up in theconsumer-side gas conduit until pressure compensation is reached and thegas stream monitor re-opens. The disadvantage is that, in an emergencycase, a certain volume of leaking gas flows through the gas streammonitor even after it has been shut.

The invention is focusing on the issue of developing a gas streammonitor of the described type in which the adjustment/alteration of thereseat flow can also be made after its manufacturing. In particular, itshould also be possible to change the reseat flow after the valve hasbeen installed. According to the present invention the problem is solvedby means of a gas stream monitor, consisting of a gas-tight casing,internally equipped with a seat for a reseating body that is movableinside the casing and is kept in the open position against the flowdirection by its own weight and/or springiness, and where the flowcross-section, the surface of the reseating body and the forces aredetermined in such a manner that the gas stream monitor laves its openposition upon a defined value of the reseat flow and is moved towardsthe casing seat so that the gas conduit is shut in the shut position,and that has, outside of the casing, at least a manipulator in the formof a tappet leading into the casing interior to adjust the springpre-tension and/or the stroke of the reseating body.

Thus, a solution has been found that abolished the disadvantages of theprior art where the adjustment of the reseat flow was only possible byinterference in the interior of the gas stream monitors, which is nowalready provided for during manufacturing.

Further advantageous arrangements of the invention are described in theother patent claims. It is, e.g., possible to arrange two or more reseatbodies in parallel inside the casing, each of which reseat bodies beingassigned with a manipulator with a tappet leading into the casinginterior to facilitate the adjustment of the spring pre-tension and/orthe stroke of the reseat body.

It is particularly advantageous when the manipulator to adjust thepre-tension and/or the stroke of the reseat body can also be used toadjust the shut position of the reseat body. Thus, it is possible thatthis gas stream monitor can additionally act also as a shut-off valve.

Favourably for the adjustment/alteration of the reseat flow of the gasstream monitors the manipulator is supported by a sliding block which,e.g., can be equipped with lock-in positions for preferential values ofthe reseat flow.

A further arrangement of the invention is that the reseat body in theshut position can be moved out of the shut position by means of a keybutton operable from outside. Thus it is possible, following theremediation of the defect and shutting of all consumers, to initiate apressure build-up in the consumer-side gas conduit until pressurecompensation is achieved and the gas stream monitor remains open. Anoverflow aperture is not necessary and thus a gas-tight closurepossible.

Particularly favourable is the embodiment in which the slide block has acontrol slope and the tappet is simultaneously interlocked with thereseat body shaft that, upon actuation of the manipulator, the reseatbody is movable from its shut position by means of the control slope andthe manipulator automatically leaves the range of action of the controlslope. This solution does not require a separate key button since thekey button function is integrated into the manipulator. Also theotherwise required through boring in the casing is not necessary.

In order to change the adjusting value of the reseat flow the reseatstroke can be altered in the place of a springiness alteration. This ispossible since the connection between manipulator and tappet isadjustable, i.e. the insert or thread depth of the tappet can bealtered.

BRIEF DESCRIPTION OF THE DRAWINGS

Below is a more detailed description of the invention by means of apractical example. The figures show the following:

FIG. 1 shows a gas stream monitor according to the invention as aschematic sectional view in an open position,

FIG. 2 shows a gas'stream monitor according to the invention as aschematic sectional view in a shut position,

FIG. 3 shows a gas stream monitor according to the invention as aschematic sectional view in a shut position after actuation of the keybutton,

FIG. 4 shows a gas a stream monitor according to the invention as aschematic sectional a view in shut position with a different key buttondesign,

FIG. 5 shows a gas stream monitor according to the invention as aschematic sectional view in a shut position with stop valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The gas stream monitor according to the invention shown in FIG. 1 has abarrel-type casing 1 with a bottom-mounted gas outlet 2 and, in thispractical example, a gas inlet 3 arranged at a right angle to it.Naturally, each have a connection for a gas conduit which, in this case,is a threaded connection at gas outlet 2. Other connections are, ofcourse, also possible.

The casing 1 is closely covered with a gas-tight cover 4, e.g. by meansof an intermediate flat packing 5. At its centre the cover 4 has asleeve-type extension 6 that projects into the casing 1 and ispreferably connected as one piece with the cover 4, in which a tappet 7is guided so that it can longitudinally move and rotate, and whose endprojecting from the cover 4 is equipped with a manipulator 8 that isfirmly connected with the tappet 7. An O-ring 9 is located at thelead-through point of the tappet 7 through the cover 4 to ensuregas-tightness.

At its perimeter in the casing 1 but outside of the extension 6 thetappet 7 has a circumferential collar 10 which supports a pressurespring 1 1 whose other end presses against the cover 4. Thus, themanipulator 8, that has two opposing poles 25 for this purpose facingthe cover 4, are non-positively drawn with the fronts of the poles 25against a circular collar that serves as a stop and is located at theside of the cover 4 that is averted from the casing 1. The height isthis collar is such that it forms in each case a slide block 12 forevery pole 25 of the manipulator 8. Both slide blocks 12 are separatedby a transverse slot that is not shown in the figure and whose functionis explained elsewhere.

The front end of the tappet 7 in the casing i is provided with a pocketboring 13, in which the lengthwise movable shaft 14 of a reseat body 15is guided to which a valve seat 16 is assigned that is connected as onepiece with the bottom of the casing 1 and by which the gas outlet 2 istightly closed in shut position (FIG. 2). In order to ensuregas-tightness in any case the reseat body 15 has, at least in thesealing area, an additional elastic packing 17. In gas outlet 2 apressure spring 19 is supported by a circumferential step 18 whose otherend exerts pressure on the reseat body 15 in opening direction.

In addition, the casing 1 has at its perimeter a radial boring 20 at theelevation of the reseat body 15 in shut position into which a tappet 21is inserted in a gas-tight manner, as in this practical example by usingam O-ring 24, and can be moved by means of an outside actuated keybutton 22 against the force of a pressure spring 23 lengthwise so farthat the lateral deflection of the reseat body 15 will cause an openingslot, despite its being in shut position (FIG. 3).

The length of the tappet 7 is determined in such a way that its front isresting on the reseat body 15 and thus presses the latter into the shutposition when the poles 25 are in the above-mentioned transverse slot ofthe cover 4. The area of the reseat body 15 which supports the tappet 7,i.e. in this case the transition of the reseat body 15 to the shaft 14,is formed in such a manner that in this shut position a lateraldefection of the reseat body 15 by means of the key button 22 is safelyprevented since there is no slack (FIG. 5).

FIG. 4 shows the gas stream monitor with a different key button design.The key button function is integrated into the manipulator 8 so that theboring 20 in the casing 1, that was necessary in the above practicalexample, is prevented. The shaft 14 of the reseat body 15 was providedwith a contraction 26 in the transition area in which the intemallycranked end 27 of t he tappet 7 can slide. Simultaneously the slideblock 12 was located inside the manipulator 8. A web 28 attached to thecover 4 projects into the slide block 12.

In addition to the shut-off position 29 and, for the sake of clarity, inthis practical example the only normal position 30 for the flow to bemonitored the slide block 12 has a control slope 31.

The mode of action of the gas stream monitor according to the inventionis as follows:

Normally the gas stream monitor is in the position shown in FIG. 1 wherethe reseat body 15 is kept in the open position by the pressure spring19 and the existing differential pressure across the gas stream monitor.If there is a gas consumption in excess of the reseat flow, due to adamaged downstream gas conduit or a defective downstream consumer thedifferential pressure increase overcomes the force of the pressurespring 19 and the reseat body 15 moves into the shut position (FIG. 2).Gas supply is interrupted. After the remediation of the defect andshutting of all downstream consumers the key button 22 is actuated andthe reseat body 15 laterally deflected and an opening slot is formed sothat there is a pressure build-up on the consumer side that makes thereseat body 15 lift from the valve seat 16 (FIG. 3).

In the practical example in FIG. 4 the manipulator 8 is actuated in theplace of the key button 22 in such a manner that the web 28 activatesthe control slope 31. Thus, the reseat body 15 is moved from out of itsshut position by the end 27 of the tappet 7 positioned in thecontraction 26 so that also an opening slot is formed with theabove-mentioned consequences. Upon releasing the manipulator 8 the forceof the pressure spring 11 deactivates the control slope 31 and themanipulator 8 is returned into its normal position 30.

A changing of the adjusted reseat flow requires the alteration of theposition of the poles 25 at the slide block 12 assigned to them. Thestroke of the tappet 7 that occurs when the manipulator 8 is turnedshifts the open position of the reseat body 15 and thus changes theeffective force of the pressure spring 19 which results in a correctionof the reseat flow.

In order to shut off the gas conduit irrespective of consumption, i.e.perform the function of a shut-off valve, the manipulator 8 is to beturned until the poles 25 leave their slide block 12 and catch into thetransverse slot. Thus the tappet 7 is moved under the impact of thepressure spring 11 until it rests on the reseat body 15 and the latteron the valve seat 16. The transition slope between reseat body 15 andshaft 14 simultaneously prevents the otherwise existing and necessarylateral slack so that the valve cannot be accidentally opened with thekey button 22 (FIG. 5).

The gas stream monitor according to the invention is of course notrestricted to the depicted practical example. There are ratheralterations and modifications possible without leaving the scope of theinvention. For instance, the connections can be modified or the changeof the reseat flow can be mode by changing the location of the pressurespring 19 in the place of changing the stroke. Moreover, one casing canaccommodate several gas stream monitors, naturally with their own gasoutlets, or the slide block 12 can have lock-in positions.

The adjusted value of the reseat flow can also be changed by alteringthe reseat stroke in the place of the springiness. This is possiblesince the connection between manipulator and tappet is adjustable, i.e.the insert or thread depth of the tappet can be altered.

What is claimed is:
 1. A gas stream monitor to automatically shut offgas conduits, consisting of a gas-tight casing (1) that has in itsinterior a valve seat (16) for a reseat body (15) that is movable insidethe casing (1) and which is kept in open position against the flowdirection by its own weight and/or spring force, in which the flowcross-section, surface area of the reseat body (15) and forces aredetermined in such a manner that reseat body (15) leaves its openposition upon a defined value of the reseat flow and is moved towardsthe valve seat (16) of the casing (1) so that the gas outlet (2) isclosed in the shut position and a manipulator (8), arranged outside ofthe casing (1), that has a tappet (7) projecting into the casing (1)interior which is used to adjust the spring pre-tension and/or thestroke of the reseat body (15), characterised in that the manipulator(8) is supported by a slide block (12).
 2. A gas stream monitor toautomatically shut off gas conduits according to patent claim 1,characterised in that die slide block (12) has lock-in positions.
 3. Agas stream monitor to automatically shut off gas conduits according topatent claim 2, characterised in that the slide block (12) has a controlslope (31) and that, in addition, the tappet (7) is interlocked with theshaft (14) of the reseat body (15) so that an actuation of themanipulator (8) can move the reseat body (15), under the impact of thecontrol slope (31), out of its shut position, with the manipulator (8)automatically leaving the range of action of the control slope (31)after the completed actuation.
 4. A gas stream monitor to automaticallyshut off gas conduits according to one of the patent claim 3,characterised in that connection between manipulator (8) and tappet (7)is adjustable.
 5. A gas stream monitor to automatically shut off gasconduits according to one of a the patent claim 4, characterised in thatthe shut position of the reseat body (15) can be adjusted with themanipulator (8) via the tappet (7) projecting into the interior of thecasing (1).
 6. A gas stream monitor to automatically shut off gasconduits according to one of the patent claim 5, characterised in thattwo or more reseat bodies (15) are arranged in parallel inside thecasing (1) with each of the reseat bodies (15) being assigned amanipulator (8) with a tappet (7) projecting into the casing (1)interior that facilitates an adjustment of the spring pre-tension and/orthe stroke of the reseat body (15).
 7. A gas stream monitor toautomatically shut off gas conduits according to patent claim 1,characterised in that the slide block (12) has a control slope (31) andthat, in addition, the tappet (7) is interlocked with the shaft (14) ofthe reseat body (15) so that an actuation of the manipulator (8) canmove the reseat body (15), under the impact of the control slope (31),out of its shut position, with the manipulator (8) automatically leavingthe range of action of the control slope (31) after the completedactuation.
 8. A gas stream monitor to automatically shut off gasconduits according to claim 1, characterised in that connection betweenmanipulator (8) and tappet (7) is adjustable.
 9. A gas stream monitor toautomatically shut off gas conduits according to claim 2, characterisedin that connection between manipulator (8) and tappet (7) is adjustable.10. A gas monitor to automatically shut off gas conduits according toclaim 1, characterised in that the shut position of the reseat body (15)can be adjusted with the manipulator (8) via the tappet (7) projectinginto the interior of the casing (1).
 11. A gas monitor to automaticallyshut off gas conduits according to claim 2, characterised in that theshut position of the reseat body (15) can be adjusted with themanipulator (8) via the tappet (7) projecting into the interior of thecasing (1).
 12. A gas monitor to automatically shut off gas conduitsaccording to claim 3, characterised in that the shut position of thereseat body (15) can be adjusted with the manipulator (8) via the tappet(7) projecting into the interior of the casing (1).
 13. A gas streammonitor to automatically shut off gas conduits according to claim 1,characterised in that two or more reseat bodies (15) are arranged inparallel inside the case (1) with each of the reseat bodies (15) beingassigned a manipulator (8) with a tappet (7) projecting into the casing(1) interior that facilitates an adjustment of the spring pre-tensionand/or the stroke of the reseat body (15).
 14. A gas stream monitor toautomatically shut off gas conduits according to claim 2, characterisedin that two or more reseat bodies (15) are arranged in parallel insidethe case (1) with each of the reseat bodies (15) being assigned amanipulator (8) with a tappet (7) projecting into the casing (1)interior that facilitates an adjustment of the spring pre-tension and/orthe stroke of the reseat body (15).
 15. A gas stream monitor toautomatically shut off gas conduits according to claim 3, characterisedin that two or more reseat bodies (15) are arranged in parallel insidethe case (1) with each of the reseat bodies (15) being assigned amanipulator (8) with a tappet (7) projecting into the casing (1)interior that facilitates an adjustment of the spring pre-tension and/orthe stroke of the reseat body (15).
 16. A gas stream monitor toautomatically shut off gas conduits according to claim 4, characterisedin that two or more reseat bodies (15) are arranged in parallel insidethe case (1) with each of the reseat bodies (15) being assigned amanipulator (8) with a tappet (7) projecting into the casing (1)interior that facilitates an adjustment of the spring pre-tension and/orthe stroke of the reseat body (15).